Stacking mechanism



March 30, 1965 R. H. MEIER 3,175,323

sacrum MECHANISM Filed May 16, 1963 3 Sheets-Sheet 1 R. H. MEIER STACKING MECHANISM March 30, 1965 3 Shets-Sheet 2 Filed May 16, 1963 March 30, 1965 V R. H. MEIER 3,175,823

STAGKING MECHANISM Filed May 16, 1965 3 Sheets-Sheet 5 United States Patent 3,175,823 STACKING MECHANISM Rudolph H. Meier, Ottawa, Untario, Canada, assignor to Her Majesty The Queen in the Right of Canada as represented by The Postmaster General, Ottawa, n-

tario, Canada Filed May 16, 1963, Ser. No. 289,886 Claims. (Cl. 271-2) This invention relates to a mechanism for stacking fiat articles and particularly for stacking items of mail (letters, post-cards). Although the mechanism is also applicable to the stacking of record cards and the like, one of its main advantages is its ability to handle dissimilar as well as similar articles, and this characteristic is particularly useful in the handling of letter mail, since letters vary substantially in length, height, thickness, weight and texture. The invention will therefore be exemplified with reference to the stacking of letter mail, since this is generally a more difficult task than the stacking of a uniform group of cards.

In post oifice operations stacking mechanisms are often associated with coding desks in which the letters are displayed individually and sequentially to an operator by means of a display window. The operator reads the address on each letter and operates a keyboard to impose a code marking on the letter oorrespording to its destination, such code marking later being used to control sorting processes. As each letter is coded in this way it is removed from the display window in front of the operator 0 to be replaced by the next letter, this process continuing at quite a rapid rate. Alternatively, the opera-tors keyboard may operate sorting gates or the like directly, without the interposition of code markings.

The travel oi the letters into and out of the display window will be edgewise, that is to say in the direction of the plane in which each letter lies rather than transversely thereto. After leaving the display window, it is often necessary to stack the letters face to face for subsequent removal to a sorter. Alternatively, if sorting follows directly, the sorted letters will need to be stacked in the various stacks-rs to which they are selectively distributed. In either case, there is need for mechanisms that can receive successive letters edgewise and stack these letters face to face in a stacker. Such stacking of the letters involves an initial edgewise movement of each letter to a position in alignment with the stacker and then a transverse displacement of the letter to move it across into the stacker.

Various such stacking mechanisms have already been developed, but they exhibit certain disadvantages, principally complexity and the problems arising out of an intermittent action, namely excessive mechanical wear and a tendency to be noisy in operation. Timing difficulties also often arise and the overcoming of these introduces further complexity and cost.

The object of the present invention is to provide an improved stacking mechanism and in particular a stacking mechanism that is improved in respect of the foregoing disadvantages.

This object is achieved by means of a stacking mechanism comprising an endless conveyor, an elongated span of which is mounted so as to present an upwardly facing supporting surface on which a flat article is deposited in an edgewise standing position at a first location along the span, the conveyor being driven to move its surface linearly and the article thereon edgewise towards a second location Where a stop arrests further movement of the article with the conveyor. A barrier projects upwardly from the conveyor surface, this barrier extending slantwise along and across the conveyor so that when it encounters an arrested article it deflects the same transice versely of the conveyor towards a suitable structure for accumulation of a stack of such articles.

Preferred embodiments ot the invention are illustrated in the accompanying drawings. It is to be understood that these illustrations are provided by way of example only, the scope of the invention being limited solely by the appended claims.

In the drawings:

FIGURE 1 is a plan view of the full opened-out length of a conveyor to be used in a mechanism of the invention;

FIGURE 2 is a perspective view of a fragment of the conveyor of FIGURE 1 on an enlarged scale;

FIGURE 3 is a plan view of a stacker mechanism employing the conveyor ocE FIGURES 1 and 2;

FIGURE 4 is a side eleavtion of the mechanism of FIGURE 3;

FIGURE 5 is a section on the line VV in FIGURE 4;

FIGURES 6a to 6f are diagrams illustrating the operation of the mechanism of FIGURES 3 to 5; and

FIGURE 7 is a plan view of an alternative construction.

FIGURES l and 2 illustrate a flexible conveyor 19 composed of a number of links 11 pivotally connected together by hinges l3 and carrying upstanding plates 13. The plates 13 are longer than the widths of the links and thus project beyond the sides of their respective links to overlap one another and form barriers that are eilectively unintenupted even when the conveyor 10 is led around sprocket wheels in the manner shown in FIGURE 4. The series of plates 13 form three separate barriers: a first continuous side barrier 14 extending uninteriuptedly along one edge of the conveyor ill; a second side barrier 18 which extends uninterruptedly along the other edge of the conveyor It except for a gap 19; and a slanting barrier 15 which extends from one end 16 adjacent the first side barrier 14 slantwise across the conveyor 10 to an end 17 adjacent one end of the second side barrier 18.

FIGURE 1 shows the full, opened-out length of the conveyor it and indicates by the dotted portions at the ends the manner in which it cfiiectively repeats itself when the two ends 20 and 21 are joined together by a hinge pin 12 to form the endless conveyor that is shown in FIGURES 3 to 5 mounted on a pair of sprocket wheels 22 and 23, the latter of which is power driven by a shaft 24 by a motor (not shown).

A letter, such as the letter 25 (FIGURES 3 and 4), is conveyed from the preceding instrumentality, such as a coding desk display Window, by conveying means terminating in a pair of rollers 26. These rollers propel the letter 25 unto the upwardly facing supporting surface of the upper span of the conveyor lit at one end of such span, and the letter then travels with the conveyor until it strikes a stop 27 extending across the top of the conveyor 10 in transverse alignment with the end Wall 28 of a stacker 29. The stacker will conveniently be of the conventional type in which letters are stacked against a gentle spring pressure applied through a movable backing plate 3%. As indicated in FIGURE 4, the stop 27 is at a level such as to be in the path of travel of the shortest letter (in vertical dimension) for which the apparatus is designed.

The position along the conveyor 10 at which the letter 25 is positioned by rollers 26 is immaterial. Assume that the letter 25 is placed on the conveyor in the position in relation to the slanting barrier 15 shown in FIGURE 3. This same condition is illustrated diagrammatically in FIGURE 6a. FIGURE 6b shows the mechanism a moment later. The letter 25 initially travels downstream with the conveyor 10. Some slight slippage may occur. If it does, it is in no way harmful. For all practical purposes there is no relative motion between the conveyor It) and the letter 25 at this time, and the letter remains in the same relationship to the slanting barrier 15 until it strikes the stop 27 (FlGURE 6c).

The letter 25 can no longer continue its travel, but the conveyor 10 continues to move and the result, as shown in FIGURE 6a, is that the slanting barrier comes to bear against the lower edge of the letter and to move it transversely and out through the gap 19 in the side barrier 18 in the manner demonstrated in FIGURE 60. As the conveyor It continues its travel, the letter is prevented Ifrom re-emerging from the stacker 2'9 by the side barrier 18 (FlGURE 6f). When the gap 19 again comes around to a position alongside the stacker 29, either another lette'r will be on the conveyor and will push back the letter 25, or, if there is no further letter on the next revolution, the letter 25 may creep outwardly of the stacker to reengage the end of the barrier 15, when it will immediately be moved back again. In either event no letters can reernerge permanently from the stacker. If preferred, a different stacking arrangement can be used in which each letter, on being deflected to the side of the conveyor, slides down a chute onto the top of a stack. In such an arrangement there is no need for the side barrier it; on the conveyor. Some provision must be made in practice to prevent the foot of the letter from sliding off one side or other of the conveyor, which is the reason for having side barriers 14 and 18. However barrier 14, and also barrier 18 (if the stacker does not tend to push the letters back onto the conveyor) may be replaced by suitable fixed side walls located beside the edges of the conveyor, except at the position where each letter is displaced transversely oil the conveyor into the stacker.

The leading edges of the plates 13 can be chamfered as at 34 (FIGURE 2) to allow each letter to be smoothly guided. Similar rounding of other edges can be made as circumstances may require.

The foregoing remarks are concerned essentially with the conveyance longitudinally and transversely of the lower edge of each of the letters. Their upper edges must also be suitably guided and this guidance may conveniently take the form of a channel member 31 which initially stops any letter falling sideways. As a letter approaches the stacker 29 is upper edge can be urged towards the stacker by a spring finger 32 and a driven roller 33. These latter parts help to overcome the resistance to movement of letters already in the stacker. If the letters are slid oil the side of the conveyor down a chute, as mentioned above, finger 32 and/ or roller 33 may be dispensed with.

FIGURE 7 shows diagrammatically a modification employing a double conveyor 10 having a central barrier 14, outer barriers 18a and 18b and a pair of slanting u walls 15a and 15b extending in opposite senses from the wall 14 to the respective walls 18a and b. Stackers 229a and 2% correspond to stacker 29, except that they have been assumed to receive the letters down a chute from the conveyor or in some other manner not requiring parts equivalent to finger 32 and roller 33. This arrangement can be used to double the capacity of the mechanism by feeding letters alternately unto the two sides of the conveyor lit by means of a pair of rollers 26', one roller 26a of which is movable between the full and broken line positions in order to direct the letters unto selected sides of the conveyor 10. Alternately, a pivotable gate could be used to direct the letters to one side or another. Another valuable advantage of the double conveyor it) is the facility to make a pre-sort of the letters by the choice of which half of the conveyor each letter is directed to. Control over the movable roller 26:; or its equivalent pivotable gate can then be exercised by the operator rather than being automatically alternate.

It will be noted that FIGURE 7 also shows the belt 10' continuing downstream beyond stackers 29a and 29b to stackers 29c and 29d so that the stacking mechanism can serve the further function of a sorter. Each stacker will have a stop 27 associated with it, each of such stops being moveable between a projecting and a withdrawn position so that selection by a control circuit of the particular stop that is moved to projecting position on each side of the conveyor will determine the stacker into which each letter will be deflected.

The conveyor may be elongated as necessary to accommodate such additional stackers, and either a single slanting barrier may be used (on each side of the conveyor if the latter is double sided), or a plurality of slanting barriers may be employed on each side. It makes no difference in which position on the conveyor the letter is first placed. It will travel with the conveyor until it is arrested by the first projecting stop and it will then allow the conveyor to slide under it until the next upstream slanting barrier engages it and moves it transversely and off the conveyor.

While a form of conveyor construction has been shown shown utilising separate links and barrier plates, it will be appreciated that a continuous conveyor belt of a suitable flexible material may be employed, and the upstanding barriers may either be separately formed or comprise a continuous upstanding strip molded integrally with or otherwise secured to the letter supporting surface of the conveyor, provided of course that the material chosen is sufliciently resilient to be led without damage around the curvatures at each end of the conveyor spans. In the preferred embodiment of the invention the plates 13 overlap to maintain the barriers continuous even around the curves, and thus avoid the possibility of a letter becomlng clamped between a pair of plates. his possible type of malfunction could be avoided in other ways, such as by depositing the letter on the conveyor somewhat along from the curved end of the conveyor. It would not then be important whether the barrier plates overlap one another or not.

I claim:

1. A stacking mechanism for flat articles comprising (a) an endless conveyor,

(17) means mounting an elongated span of said conveyor to present an upwardly facing supporting surface,

(c) means for depositing a flat article edgewise on said surface at a first location along said span,

(d) means for driving said conveyor to move said surface linearly and the article thereon edgewise towards a second location,

(2) a stop at said second location to arrest movement of said article with the conveyor,

(7) a barrier projecting upwardly from said surface and extending slantwise along and across said conveyor to deflect an arrested article transversely of the conveyor,

(g) a side barrier projecting upwardly from said surface and extending along the edge of the conveyor on the side thereof to which an arrested article is deflected by the slanting barrier,

(11) the upstream end of said slanting barrier merging with said side barrier,

(i) and said side barrier being interrupted over a section extending downstream from the location of said merging to provide passage from the conveyor of a transversely urged article.

2. A stacking mechanism according to claim 1,

(a) including a second side barrier projecting upwardly from the conveyor surface and extending uninterruptedly along the edge thereof opposite the first side barrier,

(b) the downstream end of said slanting barrier merging with said second side barrier.

3. A stacking mechanism for flat articles comprising (a) an endless conveyor,

(1)) means mounting an elongated span of said conveyor to present an upwardly facing supporting surface,

(c) means for depositing a flat article edgewise on said surface at a first location along said span,

(d) means for driving said conveyor to move said surface linearly and the article thereon edgewise towards a second location,

(e) a stop at said second location to arrest movement of said article with the conveyor,

(1'') at least one additional stop,

(g) the stops being positioned at successive locations downstream of said first location,

(h) each stop being movable between a withdrawn inoperative position and an arresting position projecting into the path of travel of a said article standing edgewise on said surface,

(i) and barrier projecting upwardly from said surface and extending slantwise along and across said conveyor to deflect an arrested article transversely of 15 the conveyor. 4. A stacking mechanism for fiat articles comprising (a) an endless conveyor, (b) means mounting an elongated span of said conveyor to present an upwardly facing supporting sur- 2O face,

(c) means for depositing a fiat article edgewise on said surface at a first location along said span,

(d) means for driving said conveyor to move said surface linearly and the article thereon edgewise towards a second location,

(e) a stop at said second location to arrest movement of said article with the conveyor,

(f) a barrier projecting upwardly from said surface and extending slantwise along and across said con- (0) means for driving said conveyor to move said surface linearly,

(d) a central barrier projecting upwardly from said surface and extending longitudinally along substantially the centre of said conveyor to divide the same into two sides,

(2) a pair of slanting barriers projecting upwardly from said surface and extending slantwise along said conveyor one on each side of said central barrier,

(f) the downstream end of each slanting barrier merging with said central barrier,

(g) a pair of outer barriers projecting upwardly from said surface and extending each along an outer edge of said conveyor,

(h) the upstream end of each slanting barrier merging with a respective outer barrier,

(1') each outer barrier being interrupted over a section extending downstream from the location of such outer barriers merging with the slanting barrier,

(j) means for depositing a flat article edgewise on said surface selectively on each side of the central barrier,

(k) stop means downstream of said depositing means for arresting movement of an article with the conveyor at a selected location for transverse deflection ot the article at such location by a said slanting barnet,

(I) and means for receiving and retaining in face-toface stacked relationship a plurality of articles so deflected at successive times at the selected location.

References Cited by the Examiner UNITED STATES PATENTS 441,832 12/90 Ethridge 271-87 2,970,836 2/61 Smith 271-87 XR ERNEST A. FALLER, Primary Examinerv RAPHAEL M. LUPO, Examiner. 

4. A STACKING MECHANISM FOR FLAT ARTICLES COMPRISING (A) AN ENDLESS CONVEYOR, (B) MEANS MOUNTING AN ELONGATED SPAN OF SAID CONVEYOR TO PRESENT AN UPWARDLY FACING SUPPORTING SURFACE, (C) MEANS FOR DEPOSITING A FLAT ARTICLE EDGEWISE ON SAID SURFACE AT A FIRST LOCATION ALONG SAID SPAN, (D) MEANS FOR DRIVING SAID CONVEYOR TO MOVE SAID SURFACE LINEARLY AND THE ARTICLE THEREON EDGEWISE TOWARDS A SECOND LOCATION, 